This invention relates, in general, to integrated circuits (ICs), and more particularly, to methods of manufacturing ICs having bipolar transistors.
Bipolar Complimentary Metal-Oxide-Semiconductor (BiCMOS) ICs are used in a wide range of applications. Most of these BiCMOS ICs use homojunction bipolar transistors with limited electrical performance characteristics. Using band gap engineering, researchers have developed heterojunction bipolar transistors (HBTs) with electrical performance characteristics that are superior to those of homojunction bipolar transistors. However, the integration of these HBTs with conventional CMOS manufacturing processes is complicated. Accordingly, a need exists for a method of manufacturing heterojuniction BiCMOS ICs where the manufacturing steps specific to the HBT are modular and compatible with a wide range of conventional CMOS manufacturing processes.